Many devices have been developed to train and strengthen the muscles used in a golf swing. Typically, the known devices utilize weight and/or wind resistance. For example, the prior art discloses several devices that include a drag component and a golf club shaft or similar component. The drag component increases the wind resistance so that when a person practices his or her golf swing with the device, the muscles used in the swing are strengthened. Such devices are disclosed by Hernberg 5,310,188, Rupnik et al. 5,335,918 and Reichenbach et al. 5,415,406.
The Rupnik et al. '918 device utilizes an airfoil or wing that is connected to a golf club shaft. Similarly, the Reichenbach et al. '406 device utilizes an air-resistant blade connected to a golf club shaft. The Hernberg '188 device differs in that it utilizes a drag component that has four orthogonal fins or wings to increase the wind resistance. However, each of these devices suffers from the same shortcoming, namely, that the wind-resistance of the device cannot be varied to meet the particular needs of the individual using the device.
Smith 5,100,148 attempted to overcome this shortcoming by providing variable resistance. Smith '148 discloses a device having a shaft and a pair of wing assemblies. Each wing assembly comprises a plurality of removable wings. The wind resistance of the device can be varied by increasing or decreasing the number of wings in the wing assembly.
The difficulty with the Smith '148 device is that varying the wind resistance is cumbersome, requiring disassembly and reassembly of the device. Further, the Smith '148 device does not readily allow for a full-range of adjustment, because the wind-resistance can only be varied by the amount of wind-resistance of an individual wing. To obtain a full range of adjustment, either the wings must be quite small or a variety of wing sizes must be utilized. Either option overly complicates the process of varying the wind resistance.
Furthermore, in each of the foregoing devices, the wings extend along the shaft axis and project radially from the shaft axis. The result is that the wind resistance may tend to rotate the shaft and affect the person's grip on the shaft.